First Precision Measurement of the Parity Violating Asymmetry in Cold Neutron Capture on $^3$He

nHe Collaboration M.T. Gericke, S. Baessler,Libertad Barrón-Palos,N. Birge, James David Bowman,Clare Britton, J. Calarco,Vince Cianciolo,C. E. Coppola,Christopher Blair Crawford, D. Ezell,Nikolaj Fomin, Irakli Garishvili,Geoffrey L. Greene,Gerald Mallory Hale,J. Hamblen, Christopher Hayes,Ellen Iverson,M. L. Kabir, Merit McCrea, Paul Edward Mueller,I. Novikov, Seppo I Penttila, Eric Plemons, A. Ram'irez-Morales, Erin M Scott, Justin D. Watts, C. Wickersham University of Winnipeg, University of Western Kentucky,University of Tennessee, Universidad Autonoma de Mexico,University of Tennessee Chattanooga, University of Virginia, Oak Ridge National Laboratory,University of New Hampshire, University of Manitoba, Los Alamos National Laboratory, Western Kentucky University

arxiv（2020）

引用 11|浏览64

暂无评分

摘要

We report the first precision measurement of the parity-violating asymmetry in the direction of proton emission with respect to the neutron spin, in the reaction He(n, p)H, using the capture of polarized cold neutrons in an unpolarized active He target. The asymmetry is a result of the weak interaction between nucleons, which remains one of the most poorly understood aspects of electroweak theory. The measurement provides an important benchmark for modern effective field theory (EFT) calculations. Measurements like this are necessary to determine the spin-isospin structure of the hadronic weak interaction. Our asymmetry result is APV = (1.58 ± 0.97 (stat) ± 0.24 (sys)) × 10−8, which has the smallest uncertainty of any parity-violating asymmetry measurement so far.

查看译文

关键词

cold neutron capture,parity violating asymmetry

AI 理解论文

溯源树

样例

生成溯源树，研究论文发展脉络

Chat Paper

正在生成论文摘要